Turns out that fear-mongering is still a thing on the internet. I know, I know… Big surprise!
Tuesday an article started circulating – I’m not going to post a link, but I’m sure you can find it – suggesting that NASA was tracking a “killer” asteroid. Some outlets even called it a “Planet-killer”.
A Planet killer?! Really?
Sadly, these claims are not completely false. But, these claims are mostly false.
NASA is tracking Near Earth Objects all the time.
These is a look at all of the Near Earth Objects set to give Earth a fly-by during the month of February. The one that tabloids are claiming is the “killer” asteroid set to destroy the planet is up at the top and set to arrive this Saturday.
The asteroid is named “2002 PZ39” and it is about 500m to 1km across. And it is traveling about 34,000mph.
Looking at the available data for that asteroid, you can see that at the asteroid’s closest pass, it is going to come pretty close to Earth, astronomically speaking.
It will pass within 0.00272 au (astronomical units) of Earth. That is a pretty small number.
But, then you have to think, well what exactly is an “au” again? Well, an au is about 92 million miles.
So .00272 au is about 252,839.796 miles.
That is pretty far away. In fact, the Moon is about 239,000 miles away.
Meaning this asteroid is going to pass by about an extra 13,000 miles away from the Earth the moon. That is about as far away as New York is to Sydney. Plus 4,000 more miles. Plus how far away the moon is from New York.
A long way.
So, the asteroid is going to be flying by outside of the orbit of our Moon. So, while 0.00272 seems like a very small number, it is a small percentage of a very big number that still leave you with a pretty decently far distance.
But that is on it’s closest pass. What about this pass?
On this pass? It will come within 0.039 au. That is 3,625,276.5 miles away! More than three-and-a-half million miles! That is about 19 light seconds away.
That means when you look at the asteroid, as it passes Earth the image you see is actually of the asteroid 19 seconds ago! That is sooo far away!
And because of the speed it is traveling, if you have a telescope and can see it, you are actually seeing it where it once was, not where it actually is.
“Huh, Nick?”
This is pretty cool! So, we just talked about how at 3.6 million miles away, it takes like 19 seconds for the light to get to your eye from the asteroid. Well, since it is traveling at 34,000mph, in 19 seconds, it will have traveled 180 miles!
Cool stuff!
In Short
There is no killer asteroid ready to strike the Earth.
